Lived in the PHL/NJ area for 6 years, love me a good steak. I think Pat's has an edge over Geno's but the best are at a place called Pudge's in Norristown.
I have a couple of recommendations.
First, they will not use the same kind of peppers or bread ( with one exception, or so they claim ), you have to remember that Italian frying peppers/cubanelles/whatever you want to call them are not readily available here. You can buy them at the Corrales Growers Market but I am unaware of any place making cheesesteaks that use the correct peppers. In my mind, green bells are not a substitute, but a lot of people like them.
In the PHL area, the best steaks are made on rolls baked by the Amoroso bakery. Petitto's in Rio Rancho claims to use Amoroso bread, but it does not taste as I remember. Perhaps they are not as fresh, perhaps they are frozen/thawed. The meat and cheese they use is not close enough to the original in my mind to make the bread elevate the sandwich to anything other than slightly above average.
In my mind good steak starts with the meat. It must be rib eye and it must be thinly sliced when frozen and then cooked with onions on a hot grill. Cheese is added at the end and the gloopy insides go into a bun and are served smoking hot.
I only have found 2 contenders.
First is DG's Deli, 1418 MLK
DG's Deli
makes a good cheesesteak and is open only for lunch ( closes at 3 )
Tickles and Snooks Wings and Things 6219 Montgomery ( at San Pedro and behind Ho Ho Chinese )
Tickles & Snooks Wings 'n Things - Home
makes a better cheesesteak and is open for lunch and dinner. Because they also do amazing wings, they can make my Buffalo Beef Cheesesteak which is a basic cheesesteak without peppers, topped with blue cheese and some XHot Wing Sauce.
Plus they do fries.